diff --git a/src/bonsai/bonsai/bim/module/pset/ui.py b/src/bonsai/bonsai/bim/module/pset/ui.py
index d9c17c7992..ad656a1d4b 100644
--- a/src/bonsai/bonsai/bim/module/pset/ui.py
+++ b/src/bonsai/bonsai/bim/module/pset/ui.py
@@ -378,8 +378,10 @@ class BIM_PT_object_qtos(Panel):
                 )
         layout = self.layout
         qtoprops = context.scene.BIMQtoProperties
-        row = layout.row()
+        row = layout.row(align=True)
         row.prop(qtoprops, "qto_rule", text="")
+        # A bit confusing as we typically use this icon for is_null.
+        row.prop(qtoprops, "fallback", text="", icon="RADIOBUT_ON" if qtoprops.fallback else "RADIOBUT_OFF")
         row = layout.row()
         row.operator("bim.perform_quantity_take_off")
 
diff --git a/src/bonsai/bonsai/bim/module/qto/operator.py b/src/bonsai/bonsai/bim/module/qto/operator.py
index dfa750bd3d..fe1574d1fa 100644
--- a/src/bonsai/bonsai/bim/module/qto/operator.py
+++ b/src/bonsai/bonsai/bim/module/qto/operator.py
@@ -176,12 +176,20 @@ class PerformQuantityTakeOff(bpy.types.Operator, tool.Ifc.Operator):
         else:
             elements = set(tool.Ifc.get().by_type("IfcElement"))
 
-        rules = ifc5d.qto.rules[props.qto_rule]
+        def run_quantification(
+            rule: str, elements: set[ifcopenshell.entity_instance]
+        ) -> set[ifcopenshell.entity_instance]:
+            rules = ifc5d.qto.rules[rule]
+            ifc_file = tool.Ifc.get()
+            results = ifc5d.qto.quantify(ifc_file, elements, rules)
+            ifc5d.qto.edit_qtos(ifc_file, results)
+            not_quantified_elements = elements - set(results.keys())
+            return not_quantified_elements
 
-        ifc_file = tool.Ifc.get()
-        results = ifc5d.qto.quantify(ifc_file, elements, rules)
-        not_quantified_elements = elements - set(results.keys())
-        ifc5d.qto.edit_qtos(ifc_file, results)
+        not_quantified_elements = run_quantification(props.qto_rule, elements)
+        if props.fallback and not_quantified_elements:
+            alternative_rules = next(rule for rule in ifc5d.qto.rules if rule != props.qto_rule)
+            not_quantified_elements = run_quantification(alternative_rules, not_quantified_elements)
 
         not_quantified_message = ""
         if not_quantified_elements:
diff --git a/src/bonsai/bonsai/bim/module/qto/prop.py b/src/bonsai/bonsai/bim/module/qto/prop.py
index cdd52ed414..ec5c60cbc2 100644
--- a/src/bonsai/bonsai/bim/module/qto/prop.py
+++ b/src/bonsai/bonsai/bim/module/qto/prop.py
@@ -67,3 +67,11 @@ class BIMQtoProperties(PropertyGroup):
     qto_result: StringProperty(default="", name="Qto Result")
     qto_name: StringProperty(name="Qto Name", default="My_Qto")
     prop_name: StringProperty(name="Prop Name", default="MyDimension")
+    fallback: BoolProperty(
+        name="Fallback To Other Calculators",
+        description=(
+            "If currently selected calculator does not support quantitication "
+            "of some class/property, to try other available calculators."
+        ),
+        default=False,
+    )
diff --git a/src/bonsai/bonsai/bim/module/qto/ui.py b/src/bonsai/bonsai/bim/module/qto/ui.py
index ffd6a4f10a..49840ba4be 100644
--- a/src/bonsai/bonsai/bim/module/qto/ui.py
+++ b/src/bonsai/bonsai/bim/module/qto/ui.py
@@ -41,6 +41,7 @@ class BIM_PT_qto(bpy.types.Panel):
             row.label(text="Quantifying All Objects", icon="MOD_EDGESPLIT")
         row = layout.row()
         row.prop(props, "qto_rule", text="")
+        row.prop(props, "fallback", text="", icon="RADIOBUT_ON" if props.fallback else "RADIOBUT_OFF")
         row = layout.row()
         row.operator("bim.perform_quantity_take_off")